Saudi Arabian Oil Company

Jun Gao

Hyung Tae Kwak

Marwah Mufid AlSinan

Ahmad Mubarak Al-Harbi

Abdulaziz S Al-Qasim

Ahmad Mubarak Alharbi

Jinxun Wang

Abdulkareem AlSofi

Ali AlYousef

Zuhair A Yousif

Described is a method for evaluating oil recovery. The method includes performing a pre-coreflood process, a coreflood process, and a post-coreflood process. The pre-coreflood process includes preparing heterogenous cores samples with different structural configurations. The coreflood process includes injecting a treatment into the core samples and obtaining nuclear magnetic resonance (NMR) measurements of the treated core samples. NMR measurements are compared to assess performance of the treatment. The post-coreflood process includes conducting an X-ray micro-computerized topography (CT) scan and a Saturate, Aromatic, Resin, and Asphaltene (SARA) analysis on the treated core samples.

Method for evaluating advanced conformance control, sweep efficiency, deep diversion, and water shutoff treatments

Hydrocarbon extraction may be coupled with subterranean hydrogen storage. For example, a method of hydrocarbon extraction and hydrogen storage may include: introducing carbon dioxide into a subterranean formation via one or more injection wells, the subterranean formation containing hydrocarbons and optionally water; mobilizing at least a portion of the hydrocarbons in a hydrocarbon-bearing zone of the subterranean formation with the carbon dioxide; after mobilization with the carbon dioxide, producing the hydrocarbons from the hydrocarbon-bearing zone of the subterranean formation via one or more production wells; introducing hydrogen to the subterranean formation via the one or more injection wells, the hydrogen displacing the carbon dioxide downward in the subterranean formation; storing the hydrogen in the subterranean formation above the carbon dioxide; and producing at least a portion of the hydrogen from the subterranean formation via the one or more production wells, the one or more injection wells, or any combination thereof.

Carbon dioxide enhanced hydrocarbon recovery methods coupled with underground hydrogen storage

A method includes providing an injection well extending from a surface into a formation and alternatingly pumping a foam injectant and a gel injectant into the injection well, wherein the foam injectant includes a liquid phase with a surfactant and water and a gas phase and the gel injectant includes a water-soluble polymer and a crosslinker. The foam injectant and the gel injectant are injected at separate times and sequentially.

Methods for foam and gel injections into a well and enhanced foaming and gelations techniques

A method for determining the pore size distribution in a reservoir, including the steps: drilling a core sample out of the reservoir, determining a porosity distribution along the core sample, obtaining T-distributions at different saturation levels of the core sample with formation brine, performing time domain subtraction on the T-distributions to obtain T-distributions at all saturation levels, determining the pore throat size distribution along the core sample, determining first porosities from the T-distributions that correspond to second porosities of the pore throat size distribution for each saturation level, determining T-distributions at the first porosities from the T-distributions, determining pore throat sizes at the second porosities from the pore throat size distributions, plotting the pore throat sizes as function of the relaxation times Tto obtain the surface relaxation, and determining the pore size distribution of the reservoir.

Method for determining the pore size distribution in a reservoir

A method includes saturating a core sample with a hydrocarbon fluid to provide a hydrocarbon-saturated core, placing the core into a first aqueous fluid, applying an external force at increasing magnitude to the hydrocarbon-saturated core to displace a volume of the hydrocarbon fluid in the hydrocarbon-saturated core with the first aqueous fluid at each pressure magnitude, measuring a volume of displaced hydrocarbon fluid at each pressure magnitude, obtaining a first capillary pressure curve, re-saturating the core sample, placing the hydrocarbon-saturated core into a second aqueous fluid having a wettability altering agent, applying an external force at increasing magnitude to displace a volume of the hydrocarbon fluid in the core with the second aqueous fluid at each pressure magnitude, measuring a volume of displaced hydrocarbon fluid at each pressure magnitude, obtaining a second capillary pressure curve, and calculating a contact angle of the second aqueous fluid.

Centrifuge method for evaluating contact angle and wettability alteration

A method includes deriving spatial permeability along a core axis by saturating the rock with an aqueous solution, performing TNMR on the saturated rock to detect spatial NMR data along the core axis, desaturating the rock, performing TNMR on the desaturated rock to detect spatial NMR data along the core axis, determining the spatial cutoff data for the saturated and desaturated rock along the core axis, and analyzing the spatial NMR data. The method further includes deriving spatial permeability along a second core axis by additionally performing TNMR on the saturated rock to detect spatial NMR data along a second core axis, performing TNMR on the desaturated rock to detect spatial NMR data along a second core axis, and determining the spatial cutoff data for the saturated and desaturated rock along the second core axis.

Method for measuring the spatial water permeability profile of porous media by using non-destructive nuclear magnetic resonance technique

A method may include obtaining first nuclear magnetic resonance (NMR) data for a saturated core sample regarding a geological region of interest. The method may further include determining, using the first NMR data, spatial porosity data based on the saturated core sample. The spatial porosity data may describe various porosity values as a function of a sampling position of the saturated core sample. The method may further include obtaining second NMR data for a desaturated core sample regarding the geological region of interest. The method may further include determining, using the second NMR data, spatial permeability data based on the desaturated core sample. The method may further include determining a geological model for the geological region of interest using the spatial porosity data, the spatial permeability data, and a fitting process.

Method and system for determining geological models using spatial properties based on nuclear magnetic resonance data

A porosity model of a core sample obtained from a subterranean formation is determined. The porosity model includes a macroporosity group and a microporosity group. A nuclear magnetic resonance (NMR) measurement is performed to obtain an NMR Tdistribution of the core sample at 100% water saturation. A desaturation step is performed on the core sample. An NMR measurement is performed for the desaturation step to obtain an NMR Tdistribution of the core sample. A resistivity index of the subterranean formation is determined at least based on the porosity model and each of the NMR Tdistributions.

Determining saturation in low resistivity pay zones

A method includes screening heterogeneity of a rock sample using nuclear magnetic resonance testing to determine a composition of the rock sample, drilling at least one smaller rock sample representative of the determined composition, and testing the at least one smaller rock sample with mercury injection capillary pressure to obtain a capillary pressure distribution of the at least one smaller rock sample. The method further includes decomposing a Tdistribution from the nuclear magnetic resonance testing and the capillary pressure distribution using Gaussian fitting to identify multiple pore systems, where the small ends of the Gaussian fitted Tdistribution and the Gaussian fitted capillary pressure distribution are overlapped for at least one of the identified pore systems.

Combined discrete gaussian analysis of MICP and NMR T2 distributions of multi-modal carbonate rocks

A nuclear magnetic resonance (NMR) logging system and method is disclosed. The method may include obtaining an NMR well log, a measured downhole temperature, and at least one rock sample for a formation in a subsurface region. The method may further include determining an NMR distribution for each sample and selecting a set of samples based on the determined NMR distribution. For each selected sample, the method may further include determining a first parameter of the NMR distribution, a regression parameter of a relationship, and a first and second fractal parameters of the NMR distribution. The method may further include determining a second parameter of the NMR distribution based on the first and second fractal parameters, the regression parameter, and the downhole temperature. The method may still further include determining a parameter of the formation based on the second parameter of the NMR distributions of the set of samples.

Method and system using nuclear magnetic resonance well logging for Tcutoff value estimation

A method for determining pore size distribution of rocks is provided. Capillary pressure measurements on rock cores are analyzed to determine a pore size distribution, with smaller pores requiring greater capillary pressure to relinquish contained fluid. Large pores with rough surfaces introduce inaccuracies in determining the pore size distribution. Embodiments of the invention correct the rough surface induced inaccuracies by measuring the shift in NMR T2 distribution from full saturation to the current state of desaturation and subtracting the T2 contributions in the desaturated state that have smaller T2 values (i.e., smaller transverse relaxation time) than the smallest T2 values (i.e., shortest transverse relaxation time) in the saturated distribution.

Method to determine pore size distribution of rocks with rough surface from capillary pressure by nuclear magnetic resonance

Embodiments relate to methods for assessing inaccessible pore volume for polymer flooding. The methods include utilizing nuclear magnetic resonance to monitor polymer-based fluid displacements into porous media. According to an embodiment, the method includes providing a core sample of a porous medium, determining a total pore volume of the core sample, introducing polymer solutions, obtaining nuclear magnetic resonance relaxation time distributions of water within the core sample, and assessing the inaccessible pore volume.

Assessment of inaccessible pore volume for polymer flooding

A method for characterizing wettability of a porous medium is described. A core sample of the porous medium is secured in a core holder, which includes a first end and a second end. A model of the core sample and a pore volume of the core sample are obtained. A wetting phase is displaced from the core sample by supplying a non-wetting phase at one end of the core holder. The non-wetting phase is displaced from the core sample by supplying the wetting phase at one end of the core holder. A saturation profile of the core sample is determined based on cross-sectional images of the core sample. A wettability index value is calculated at least based on a comparison of the saturation profile and the model of the core sample.

Measuring rock wettability

A method of estimating a property of a porous media including: saturating a sample of the porous media with a fluid; spinning the sample in a centrifuge; obtaining a saturation profile of the sample; identifying a portion of the sample in which saturation of the sample is within 10% of a minimum saturation of the sample; and measuring a first property of the porous media on the identified portion of the sample.

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Al Khobar, Saudi Arabia

Jun Gao